why are the images visible in the APK file and is there a way to hide them

The app images (png) in the drawable folder can easily be extracted with a zip tool.

Was thinking that开发者_Go百科 an APK file would be more "closed".

Is this normal?

Is there some way to fix this?

Is this normal?

Absolutely.

Is there some way to fix this?

No, because there is nothing to "fix". Anybody capable of getting at your APK file is also capable of getting at your images wherever else they might be stored (e.g., downloaded from the Internet and cached in on-board flash). And anybody using normal SDK tools can take screenshots of your app and get at your images that way. Protecting images is a pointless exercise.

An APK is really nothing more than a compressed archive. It is completely normal for the PNGs to be accessible from the unzipped APK. Its going to be nearly impossible to prevent a resourceful hacker from getting your images if they want to. You can do things to prevent it but it is going to be more of a headache then its worth.

If you really want to keep the drawables out of the APK you could simply download the drawables from a website the first time your applications loads. This however has other problems because you would then have to prevent unauthorized downloads of the drawables.